DIYARBAKIR, Turkey (Reuters) - Two soldiers were killed and one wounded when a roadside bomb detonated by Kurdish militants hit a passing military vehicle in Turkey's largely Kurdish southeast on Wednesday, security sources said.

The bomb was detonated by remote control as the vehicle passed through a highway near Siirt, in southeast Turkey, the sources said.

Members of the outlawed Kurdistan Workers Party (PKK), which has waged a three-decade insurgency against the Turkish state, frequently target military and security force cars and trucks with roadside bombs.

Air-backed operations had been called in to target militants in the region, the sources said. Troop reinforcements and helicopters had been dispatched, they said.

The mainly Kurdish southeast has been scorched by some of the worst fighting since the height of the insurgency in the 1990s, after a ceasefire between the state and the PKK fell apart in July last year.

(Reporting by Seyhmus Cakan in Diyarbakir and Humeyra Pamuk in Istanbul; Writing by David Dolan; Editing by Toni Reinhold)